DE102007040609B4 - Method for producing a cable-like spring element semifinished product, a spiral-shaped spring element, a tool for processing a cable-like spring element semifinished product, device for producing a spiral-shaped spring element - Google Patents

Abstract

A method of producing a rope-like spring element semifinished product (10), comprising the following steps: a) providing an elastically and reversibly compressible spring core body (20) of a reinforcing fiber sheath surrounding the spring core body (20) and comprising at least one fiber filament (32) (30); b) impregnating at least the reinforcing fiber sheath (30) with a liquid or pasty curable matrix material (78) and thereby establishing a preliminary mutual arrangement of the spring core body (20) and the reinforcing fiber sheath (30) and forming a predetermined one Cross-sectional shape of the spring element semifinished product (10), wherein the spring element semifinished product (10) is compressed during impregnation and / or after impregnation and thereby elastically and reversibly deformed, and wherein during the compression of the spring core body (20) is compressed and thus by means of Spring core body (20) directed against the inside of the reinforcing fiber sheath (30) counter pressure is generated.

Description

The invention relates to a method for producing a cable-like spring element semifinished product, a method for producing a helical spring element, a tool for processing a cable-like spring element semifinished product and a device for producing a helical spring element.

Conventional spring elements made of steel require a large cross-section at high loads and therefore have a large weight, are dynamic only slightly resistant to change and susceptible to corrosion.

Furthermore, rope-like spring elements are known, which consist of fiber composites. Such coil springs are particularly suitable for absorbing torsional stresses. In addition to cylindrical coil springs also flat coil springs or springs with rectangular cross-section are known.

However, the production of such spring elements made of fiber composites designed as very difficult.

DE 30 37 616 A1 discloses a method of producing a fiber reinforced plastic coil spring in which a strand of fibers and resin is wound on a spiral groove core (rotor), then cured and finally removed from the core.

DE 693 21 050 T2 discloses a structural member having a core disposed within a hollow sheath wherein the core is formed of fibers and the sheath of reinforcing filaments. For the production of the structural element, a manufacturing method is described.

DE 30 31 582 A1 discloses a fiber-reinforced plastic helical member having an outer bendable sheath, an underlying layer of wire or ribbon of cured fiber reinforced material wound over a hollow or full core. The sheath may be a wound foil or a tube.

The invention has for its object to provide measures in the context of the production of a spiral spring element and such a spring element, which is easy to produce, especially in the continuous process. Furthermore, different cross-sectional shapes to produce and the spring element can be used in many ways.

This object is solved by the subjects of claims 1, 13, 16, and 23. Advantageous embodiments of the invention are the subject of the dependent claims.

An idea of the invention is accordingly to provide a spring core body and a reinforcing fiber sheath surrounding the spring core body, which has at least one fiber filament, in a method for producing a cable-like spring element semifinished product. At least the reinforcing fiber sheath is impregnated with a liquid or pasty, curable matrix material and thereby a provisional mutual arrangement of the spring core body and the reinforcing fiber sheath and fixed and formed a predetermined cross-sectional shape of the spring element semifinished product, the spring element semifinished during the impregnation and / or compressed after impregnation and thereby elastically and reversibly deformed. In this case, the spring core body is also compressed during compression and so by means of the spring core body directed against the inside of the reinforcing fiber sheath counter pressure generated.

In other words, the reinforcing fiber sheath is embedded in the matrix material. This material is preferably corrosion resistant. The matrix material used is preferably a resin, in particular an epoxy resin. The cladding forms a reinforcing fiber structure. Preferably, the reinforcing fiber sheath may comprise at least one reinforcing fiber or at least one filament or a filament formed from a plurality of filaments.

Furthermore, in the production of the spring element semifinished product or of the method for producing a spiral-shaped fiber composite spring element described below, the spring core body can only represent an auxiliary body which ensures that when impregnated with the matrix material or during later winding of the "soaked" spring element semifinished product whose cross-sectional shape is largely maintained.

The spring core body can consist of a solid material or of a fiber or a fiber bundle, wherein the spring core body preferably comprises a thermoplastic or elastomeric material or a fiber material, in particular glass fiber. The materials and the one- or multi-part construction of spring core body and sheath will be explained below in particular in connection with the final fiber composite spring element to be produced.

Thus, spring core body and reinforcing fiber cladding are in the provisional mutual arrangement preferably in a loose cohesion to form spaces between the thread or bundle of filaments and the spring core body. In the final mutual arrangement, the thread or threads lie closely to each other and to the spring core body while minimizing the gaps and air pockets. Preferably, the compression takes place with the aid of a tensile force, which can be used at the same time for conveying the spring element semifinished product in the advancing direction of the method.

In other words, the spring element semifinished product is compressed by the action of pressure from the outside of the spring element semifinished product. The compression preferably takes place in and / or by means of the delivery channel.

Instead of the term spring element semi-finished product, the term "rope" is used in the following and instead of the term spring core body and the term "inner soul". Under a thread bundle is also a variety of threads, filaments or monofilaments to understand.

In a preferred embodiment of the method, the spring core body used is sealed on its outer side against penetration of the liquid or pasty, curable matrix material. Furthermore, the spring core body may be impermeable to the liquid or pasty curable matrix material. Advantageously, the spring core body is rubbery or foam-like elastic and reversible compressible.

In a further preferred embodiment, the spring core body is soaked in step b) of claim 1. When impregnating, an excess amount of the matrix material may preferably be supplied.

For impregnation, the spring core body surrounded by the reinforcing fiber sheath can be conveyed with an excess amount of the matrix material through an impregnation basin filled with the liquid or pasty curable matrix material. Preferably, the transport of the spring element semifinished by the impregnation tank is in a non-tensioned state, so that there are sufficient spaces between the individual components of the spring element semifinished, through which the matrix material as large as possible with the surface of the thread, the threads and / or the reinforcing fiber sheath and optionally, the spring core body can come into contact. In order to allow this unstressed transport through the drinking bowl, it is advantageous if there is a voltage regulator device downstream of and / or upstream of the bowl.

In another advantageous variant of the method, the spring core body surrounded by the reinforcing fiber sheath is conveyed for impregnation through a delivery channel and the liquid or pasty curable matrix material is injected into the delivery channel.

Preferably, the matrix material is injected under pressure into the delivery channel so that it can enter the intermediate spaces. In order to achieve a sufficient pressure for the supply of the matrix material, the matrix material can be supplied via an injection molding machine and be injected, for example via a plurality of holes in the delivery channel. Furthermore, it is preferred if the injection of the matrix material takes place in a region of the delivery channel in which the components of the spring element semifinished product are in the provisional mutual arrangement with the formation of intermediate spaces.

Preferably, the spring element semifinished product is transported after impregnation through a conveyor channel.

Advantageously, spring core body and reinforcing fiber sheath are largely brought into their final position to each other in the delivery channel. For this purpose, a suitably designed and described below tool with different processing zones can be used. In the event that the spring core body is not removed, the final arrangement of the reinforcing fiber sheath results after complete curing of the matrix material.

Preferably, any excess matrix material may be removed after soaking. The removal of the excess matrix material can take place via the delivery channel or by means of the delivery channel. Removed excess liquid or pasty curable matrix material can be collected and reused for soaking.

In a preferred development, the matrix material can be at least partially cured in a step c), so that the spring element semifinished product has a prepreg-like and largely dry, limp, rope-like state.

An advantage of the above-described method is that the excess matrix material can be collected and reused. Furthermore, the processing steps of the soaking and compressing can be coordinated be summarized or, so that, for example, the resulting excess matrix material at the same time allows easier transport of the spring element through the conveyor channel.

The tool according to the invention for processing a cable-like spring element semifinished product, in particular the above-described rope-like spring element semifinished product, comprises a conveyor channel through which the spring element semifinished product can be conveyed and which has a feed region, a compression region and a discharge region in the conveying direction, the conveying channel being in the conveying direction from an inlet of the Feed region to the compression region is tapered, and wherein the cross-sectional area or the diameter of the inlet of the feed region is greater than or equal to the outer diameter of the conveyed into the conveyor channel spring element semifinished product, and wherein the cross-sectional area or the diameter of the compression region smaller than the forming desired cross-sectional area or the desired outer diameter to be formed of the spring element semifinished product is.

The tool or its delivery channel makes it possible to press the matrix material into the fiber structure, to strip off excess matrix material or to inject the matrix material in the delivery channel. The semifinished product used can have an oval cross section, be conveyed through a round channel and subsequently harden with an oval cross section. This can result in particular because the spring core body decisively co-determines the later cross-sectional shape.

Thus, the delivery channel provides an elongate cavity with a cross-sectional area that changes at least in sections along the conveying direction. This cross-sectional area extends substantially transversely, in particular perpendicular, to the conveying direction. After passing through this tool, the reinforcing fiber sheath engages closely with the spring core body.

In a preferred embodiment, an injection region is provided between the feed region and the compression region, and in the region of the injection region at least one bore opens into the delivery channel, through which the liquid or pasty, curable matrix material can be fed to the spring element semifinished product. In this way, the excess matrix material pressed out in the compression region can be drained off via the supply region and / or the discharge region and returned to the impregnation.

Preferably, the cross-sectional area or the diameter of the discharge region is substantially equal to or greater than the desired cross-sectional area to be formed or the desired outer diameter of the spring element semifinished product to be formed.

Since in most cases a substantially circular or a substantially oval cross-section is selected for the cable-like spring element semifinished product, the tool is configured in a preferred embodiment such that the cross-sectional area of the feed region tapers in the conveying direction from a first diameter to a second diameter the second diameter is greater than the desired diameter of the spring element semifinished product to be formed, and wherein a third diameter of the compression region is substantially equal to or smaller than the desired diameter of the spring element semifinished product.

Furthermore, the invention shows a method for producing a helical spring element, wherein a rope-like spring element semifinished product is produced by a method as described above, and then by winding the impregnated spring element semifinished product around a shaping element having a surface which corresponds to the final geometric shape of the spring element is tuned and / or depicts it; and by completely curing the liquid or pasty, curable matrix material, the rope-like spring element semifinished product is processed to form a spiral-shaped spring element semifinished product and the spiral-shaped spring element is produced by curing from the spiral-shaped spring element semifinished product.

With this method, in particular, a spiral-shaped fiber composite spring element is to be formed or produced.

Depending on the desired cross-sectional shape of the spring element, the shaping body can, viewed in cross-section, have a substantially circular, elliptical, rectangular or similar cross-sectional shape. Furthermore, the progress speed and / or the rotational speed of the shaping body can be matched to the desired shape.

In a preferred development of the method, a further shaping body is connected to the shaping body by means of a torsion-proof, preferably form-fitting, connection. The connection of the shaping body can be done with or without interrupting the winding process. For example, the further shaping body to be connected can be driven at the same speed and a suitable relative position with respect to the other shaping body, so that the two can be moved toward each other during their preferably synchronous rotation, until the rotationally secure connection is made. In this way it is possible to produce an endless spring element by a winding method, wherein it does not have to be necessary to interrupt the winding process. In order to produce different lengths of spring elements depending on the requirements, shaping bodies of different lengths can be provided, wherein a shaping body of desired length can be provided in a simple manner by joining a plurality of shaping bodies in a simple manner.

In a preferred embodiment, the liquid or pasty, curable matrix material is cured by means of heat and / or by a photochemical reaction, in particular by means of UV radiation.

Furthermore, before winding the spring element semifinished product around the shaping body, a band, preferably a foil strip, of predetermined thickness can be wound onto the shaping element. Such a band can be removed after the completion of the molding process, whereupon the spring element can be removed more easily from the shaping body.

Furthermore, the cured, spiral-shaped spring element can be cut to a predetermined length.

In a preferred variant of the spring core body is removed after complete curing of the liquid or pasty, hardenable matrix material from the spiral spring element. In other words, the spring core body forms here an auxiliary body or support body, which is subsequently removed. This is particularly advantageous in the context of lightweight construction applications.

Furthermore, the invention relates to an apparatus for producing a spiral spring element with a hollow, tubular fiber composite spring element body, comprising a trough for impregnating a rope-like spring element semifinished product, a tool, as described above, at least one shaping body for forming the rope-like spring element semifinished into a spiral spring element semifinished product wherein the forming body has a surface tuned or contoured to the geometric shape of the helical spring element blank and having at one end a terminal for connection to another forming body, and curing means for hardening the helical spring element blank to form the helical spring element.

The spiral-like spring element semifinished product can still be present in bending-slippery form after this deformation and then, after curing of the matrix material, the desired properties, such as, for example, the elasticity and strength, can be achieved.

In an advantageous embodiment, the connection is formed rotationally fixed. Advantageously, the connection is designed to form a positive connection with the further shaping body. More preferably, the terminal has a groove and / or a spring.

Advantageously, the surface has at least one groove for spiral-like shaping of the spring element semifinished product, wherein the rope-like spring element semifinished product can be wound around the shaping element in this groove. In this way, a uniform shape can be achieved at an increased rate of progress.

In a preferred embodiment, at least one tensioning device is provided for tensioning the cable-like spring element semifinished product. At least two tensioning devices are preferably used, wherein a first tensioning device is arranged upstream and a second tensioning device is arranged downstream of the drinking basin.

Advantageously, a collecting basin is provided for collecting excess matrix material. Further, a recycle line that returns the excess matrix material from the catch basin to the potion can be provided. In order to enable a cutting of the rope-like, the helical spring element semifinished product or the spiral (fiber composite material) spring element, a separating device can be provided.

A preferred embodiment of the aforementioned manufacturing method has a method for the serial production of cylindrical coil springs constant cross section of the subject.

In addition, an object of the invention, a semi-finished fiber product (hereinafter also referred to as "rope"), which for the technical realization of o. G. Method is usable.

An advantage of the manufacturing method is that, taking advantage of the directionally oriented strength properties of fiber composites in particular, it is possible to create a machine element that is highly dynamic, resistant to change, and resistant to a large number of corrosive media.

A preferred use of the spring element according to the invention is in the field of aerospace vehicles, such as aircraft, helicopters and space ferries, in the maritime field and in other fields, where components with high strength, long life, good corrosion resistance and at the same time with a low weight are desired.

Embodiments of the invention will be explained in more detail with reference to the accompanying drawings. It shows:

1 a top view of a first embodiment of a rope-like spring element semifinished product with a spring core body and two spring bundles surrounding the spring core body;

2 to 5 several cross sections through different filament bundle arrangements;

6 a schematic cross section through a rope-like spring element semifinished with spring core body and reinforcing fiber sheath;

7 a top view of a first embodiment of a spring element semifinished product with a spring core body and a plurality of the spring core body surrounding filament bundles with opposite, interwoven winding;

8th a top view of a second embodiment of a rope-like spring element semifinished product with a spring core body and a plurality of the spring core body surrounding filament bundles with opposite, interwoven winding;

9 a view according to 1a . 1b to a third embodiment of the rope-like spring element semifinished product with a plurality of bundles surrounding the spring core body of the same direction winding;

10 a view from above of a fourth embodiment of the rope-like spring element semifinished product with a plurality of the spring core body surrounding in layers arranged thread bundles with opposite winding;

11 a schematic representation of a first variant of a method for producing a rope-like spring element semifinished product with subsequent transformation of the rope-like spring element semifinished product in a spiral spring element;

12 a sectional side view of a first embodiment of a tool for processing the rope-like spring element semifinished product;

13 a schematic representation of a second variant of the method for producing a rope-like spring element semifinished product with subsequent forming of the rope-like spring element semifinished product in a spiral spring element; and

14 a sectional side view of a second embodiment of a tool for processing the rope-like spring element semifinished product.

1 shows the basic structure of a rope-like spring element semifinished product 10 or "rope" with representation of the soul and the opposite type of winding on the basis of two filaments or threads 32 or two bundles of fibers or bundles 36 ,

The "rope soul" 20 consists of a concentric bundle combined single fibers or "ropes" to produce larger spring dimensions of a flexible, lightweight but pressure-resistant solid material, eg. As a thermoplastic foam or the like. The "soul" serves as a shaped body of the "rope" and also mainly for the transmission of tensile forces in the spring manufacturing process. The reinforcing fiber cladding 30 the soul" 20 includes at least a single thread or a single filament 32 or based thereon bundles or bundles of fibers 36 ,

The 2 to 5 show different filament bundle shapes. The forms b and c are for the production of the "rope" 20 and subsequently the spring element most favorable, as in the wrapping of the "soul" the smallest voids between the individual threads 32 or filament bundles 36 arise.

Since fiber materials are very sensitive to stress across the fiber, it is advantageous to avoid or reduce this stress that the "core diameter" is very large compared to the filament diameter of the filament bundles. However, since the filament diameter is in the micron range, the core diameter, however, in the mm range and the reinforcing fiber cladding of the "soul" is generally multi-layered, this requirement is generally met.

The thickness of the wound and woven reinforcing fiber sheath 30 is small compared to the "rope diameter". 6 illustrates the proportions of cladding layer to "rope diameter".

The 7 to 10 show further embodiments of the rope-like spring element semifinished product 10 extending in a longitudinal direction L and a spring core body 20 and a spring core body 20 surrounding reinforcing fiber cladding 30 with at least one thread 32 or a thread bundle 36 includes. As will be explained below, the spring core twill 20 used only as an auxiliary body in the context of wrapping and after production of the spring element semifinished product 10 or be removed at a later stage. Alternatively, the spring core body 20 also remain, ie then forms a part of the final spring element.

In the context of the embodiments described below, the spring element semifinished product 10 also called "rope" and the spring core body 20 also called "inner soul". Such a rope corresponds to the spring wire in conventional steel springs.

Around the spring core body 20 be used to produce the rope or spring element semifinished product 10 preferably helically, depending on the intended use of the final finished spring element, either with the same direction or opposite direction of impact, the individual threads 32 or thread bundle 36 . 37 winding or winding and interwoven.

Preferably, the wrapping of the inner soul in this way takes place in several layers. The pitch of the filament screw line is generally 45 ° with respect to the longitudinal direction L, but may differ by several degrees to achieve certain properties during processing or on the final product.

The spring core body 20 (inner soul) may consist of several combined into a concentric bundle individual fibers or of a flexible, lightweight but pressure-resistant solid body, eg. B. made of thermoplastic foam or the like. The spring core body 20 serves during the spring manufacturing process for the transmission of tensile forces, as a shaping body for the spring element semifinished product 10 and, if not removed, for partial transmission of force. As a material for the spring core body 20 For example, materials can be used which have sufficient strength properties even with transverse stress. In the case of fiber materials, glass fiber material is particularly suitable here. For larger diameters of the spring core body 20 is the use of thermoplastics or elastomers useful. For the reinforcing fiber cladding 30 forming threads 32 or thread bundle 36 . 37 In particular, high-strength fiber material, such as glass, Kevlar, coal or boron fibers are suitable. Since fiber materials are very sensitive to a load across the grain, it is advantageous to avoid or reduce this stress that the diameter of the spring core body 20 very large compared to the diameter of the thread 32 or the thread bundle 36 . 37 is. Because the diameter of the thread 32 However, in micrometer range, the diameter of the spring core body 20 However, in the millimeter range, this requirement is usually met in particular when the reinforcing fiber sheath 30 multilayered. The thickness of the wound and woven reinforcing fiber sheath 30 is small compared to the diameter of the spring core 20 ,

The 7 and 8th each show a rope-like spring element semifinished product 10 in which the spring core body 20 surrounding reinforcing fiber cladding 30 six threads 32 or thread bundle 36 includes with opposite, interwoven winding. The direction of impact is inclined at about 45 ° to the longitudinal direction L. at 8th is in addition to the in 7 shown assembly a single thread 32 or a thread bundle 37 with a different directional orientation, in the present case parallel to the longitudinal direction L, in the reinforcing fiber sheath 30 woven. In this way, certain mechanical properties of the spring element semifinished product can be achieved 10 produce. In a completed interwoven wrapping the bundles of fibers lie 36 . 37 then without gap firmly together and to the spring core body 20 at. The required number of filament bundles 36 . 37 varies depending on the type of bundle of filaments used and their structure and the desired rope diameter.

9 shows the winding principle of a spring element semifinished product 10 with only rectified around the spring core body 20 wrapped threads 32 or filament bundles 36 , To achieve a sufficient cohesion and the handling of such a rope during the subsequent forming process for spiral shaping is a thread 32 or a thread bundle 37 wound in opposite direction of impact and partly with the other bundles of threads 36 interwoven. The entire reinforcing fiber cladding 30 the inner soul 20 is built in several layers. This way unidirectionally wound ropes 10 are mainly intended for use with spring elements with only one constant loading direction.

10 shows a spring element semifinished product 10 with oppositely layered winding in several layers 38 , every layer 38 includes a plurality of filament bundles 36 which are all substantially parallel to each other and rectified. The winding direction of the individual layers 38 to each other, however, is in opposite directions. Again, in a particular layer 38 individual threads, also known as support threads, be incorporated. For better processability and handling, it is advantageous to have a very thin outermost interwoven layer 38 to install.

Generally allow the threads 32 or thread bundle 36 . 37 mutually a mechanically positive and frictional cohesion, which allows a shift against each other, without a significant change in shape and structure of the spring element semifinished product 10 to effect. This is the rope 10 flexible, elastic to a certain extent and tractable. For the inner soul 20 If a material should be used which has sufficient strength properties even with transverse stress. In the case of fiber materials, glass fiber is particularly suitable here. For larger rope diameters, the use of certain thermoplastics or elastomers is suitable. For the reinforcing fiber cladding 30 forming thread bundle 36 . 37 All high-strength fiber materials such as glass, Kevlar, coal and drilling fiber are suitable. Up to a rope diameter of about 4 mm, glass fiber is particularly suitable for the inner soul. The flexible ropes 10 can be wound on rolls and drums, stored and made available for further processing.

Two variants of a method for producing the rope-shaped spring element semifinished product are described below 10 described ( 11 . 13 ). In this manufacturing method, the above-described spring core body 20 with the spring core body 20 surrounding reinforcing fiber cladding 30 provided. Subsequently, at least the reinforcing fiber sheath 30 with a liquid or pasty, hardenable matrix material 78 soaked and thereby a preliminary mutual arrangement of the spring core body 20 and the reinforcing fiber cladding 30 set and a predetermined cross-sectional shape of the spring element semifinished product 10 educated.

The first method variant according to 11 is preferably suitable for ropes of thinner diameter. The second variant according to 13 is preferably suitable for ropes with thicker diameters.

In the first method variant according to 11 is from a pulley 70 a spring element semifinished product 10 , for example, with one in the 7 to 10 shown construction, and a not yet final cohesion of the components of the reinforcing fiber sheath 30 and the spring core body 20 over pulleys 72 unwound and provided for further processing. To demand the spring element semifinished product or rope 10 This is about a jig 74 with a rope tension regulator through a drinking basin 76 drawn. The drinking bowl 76 is with a corrosion-resistant matrix material 78 filled, preferably with liquid reaction resin, for example based on epoxy resin. The cable tension regulator of the tensioning device 74 is set in such a way that there is almost no tension on the watering bowl 76 located section of the rope 10 lies. The thread bundles 36 . 37 reinforcing fiber cladding 30 form a loose cohesion in this state, which allows the matrix material 78 due to the static pressure in the drinking basin 76 and due to capillary effects in the rope 10 penetrate and the individual threads or filaments 32 can wrap. About further pulleys 72 becomes the soaked rope 10 from the drinking basin 76 and a second tensioning device 75 with a second cable tension regulator in a nozzle-shaped tool 40 drawn. Here, the second voltage regulator is set so that the rope 10 in the area of the tool 40 taut.

12 shows this tool 40 , which for processing the rope-like spring element semifinished product 10 serves, in a cross section. The tool 40 comprises a nozzle-like shaped base body 42 with a protruding flange with holes 43 for stationary fixing of the tool 40 , The base body 42 has a continuous along the conveying direction F inner cavity, a conveying channel 44 provides.

The conveyor channel 44 is in the conveying direction F in a feed area 45 , a compression area 47 and a discharge area 48 divided. Viewed along the conveying direction F, the cross-sectional area of the conveying channel tapers 44 in the area of the feed area 45 starting from an inlet opening conical up to the compression area 47 and then expands in a steady curve to the outlet opening in the discharge area 48 , The compression area 47 This can also be formed only selectively. All transitions between the aforementioned areas are softly rounded. Preferably, as in 12 to recognize, points the delivery channel 44 a substantially circular cross section. Here, a first diameter D _e (inlet diameter) is greater than a second diameter D _k (compression diameter). Further, a third diameter D _a (outlet diameter) is larger than the second diameter D _k . Further, the first diameter D _e and the third diameter D _{a is} greater than the desired diameter of the rope 10 , The second diameter D _k as the minimum nozzle inner diameter, however, is substantially equal to or smaller than the desired diameter of the rope 10 ,

Stressed on train, the rope has 10 in particular, in the case of a rope with a counter-interwoven winding, the tendency to contract, whereby the bundles of threads 36 . 37 reinforcing fiber cladding 30 to each other and close to the inner soul 20 lay. This is excess matrix material 78 from the rope 10 squeezed out and usually remains on the rope surface be liable. This process is already done by the tensile stress to transport the rope 10 before the rope 10 in the tool 40 enters. Then the rope goes through 10 the conveyor channel 44 , wherein the excess matrix material still remaining on the cable surface 78 at least partially in the feed area 45 is stripped off.

Then the rope 10 in the compression area 47 further compressed, including the last excess matrix material 78 from the rope 10 is pressed. The excess matrix material 78 can on the inclined inner surface of the conveyor channel 44 drain and in a catch basin 80 to be collected. Via a return line 82 becomes the collected excess matrix material 78 the drinking basin 76 recycled and can be used again. As a further effect, any air pockets will be due to the initial loose cohesion of spring core 20 and reinforcing fiber cladding 30 through the nozzle-like inner shape of the conveyor channel 44 and eliminated by the pressure component of the resin directed both to the cable interior and to the inlet opening of the feed area.

Hereinafter, the second process variant according to 13 explained. As already mentioned, this variant is primarily used for processing ropes 10 larger diameter, where the impregnation in a drinking bowl is difficult. The impregnation of the rope 10 takes place in this process variant during transport of the rope 10 through the delivery channel 44 the in 14 illustrated second embodiment of the tool 40 ,

From the basic principle, the impregnation takes place here by injecting the matrix material 78 in the conveyor channel 44 , To accomplish this, the tool is different 40 the second embodiment of the first embodiment of the tool 40 according to 12 in that viewed in the conveying direction F between the feed area 45 and the compression area 47 an injection area 46 is provided. This injection area 46 has along its length a constant cross-sectional area with a fourth diameter D _l . Alternatively, a cross-sectional shape tapering in the conveying direction F can also be used for the injection area 46 to get voted. The first diameter D _e (inlet diameter), the second diameter D _k (compression diameter) and the third diameter D _a (outlet diameter) behave relative to one another as already described above in connection with FIG 12 described. The additional fourth diameter D _l (injection diameter) is substantially the same size as the desired diameter of the rope 10 and preferably larger than the second diameter D _k .

To the matrix material 78 Being able to deploy includes the tool 40 a connection 50 , a supply line 52 , a ring channel 54 and several holes 56 , The matrix material 78 is powered by a worm-driven injection molding device 58 provided under a predetermined pressure and over the terminal 50 the supply line 52 fed. About the supply line 52 becomes the matrix material 78 in the ring channel 54 passed and finally over the holes 56 in the conveyor channel 44 brought in. This allows a fast and complete impregnation of the rope 10 and thus a fast passage speed of the rope 10 through the tool 40 ,

Downstream of the injection area 46 closes the compression area 47 to the components of the spring element semifinished product 10 in a mutual position with a close to the spring core body 20 adjacent reinforcing fiber cladding 30 to press and at the same time excess matrix material 78 to remove. The derivation of the excess matrix material 78 takes place in the same way as in the first method variant, preferably via the feed area 45 , but also about the discharge area 48 respectively. After passing through the tool 40 has the rope 10 its approximate cross-sectional shape provided later and can be further processed into a spring element with a spiral shape. The final cross-sectional shape receives the spring element after curing of the matrix material 78 ,

Such further processing is described below, can follow both methods described above and is therefore both in 11 as well as in 13 shown schematically. After passing through the tool 40 The rope is now on a rotating shaping body 100 in the form of a cylinder for forming the rope-like spring element semifinished product 10 wrapped in a spiral spring element semifinished product. In this winding process are cylinder diameter, rotation and speed of progress to the desired geometry of the desired spiral spring element semifinished product 10 Voted. Preferably, the shaping body 100 a surface having a spiral groove of substantially semicircular cross-section to allow for an accurate winding.

To achieve a continuous manufacturing process, several shaping bodies can 100 . 102 . 104 be joined together with identical trained surface and the same or different length. For this purpose, each shaping body 100 . 102 . 104 a first end 107 and a second end 108 on, being at the two ends 107 . 108 one connection each 110 to twist-proof connection with each adjacent shaping body 100 . 102 . 104 is provided. The connection 110 is preferably formed such that the adjacent shaping body 100 . 102 . 104 can be positively connected with each other, for example, with a tongue and groove connection, either during the continuous manufacturing process, ie rotating forming bodies 100 . 102 . 104 or at an interruption of the winding process.

After completed winding, the molded and cured (Faserverbundwerkstoff-) spring element 200 slightly from the forming body 100 to be able to decrease, in a preferred embodiment, prior to winding of the spring element semifinished product 10 a foil tape 116 wound up on the surface. Later, the foil tape 116 under the fiber composite spring element wound on the forming body 200 be pulled out, so that a certain clearance or space is created and the fiber composite spring element 200 more easily from the forming body 100 can be removed.

As an alternative to a groove-like surface, the shaping body can 100 . 102 . 104 be designed as a simple round cylinder. In this case, it comes during the winding of the spring element semifinished product 10 to a slight flattening of the substantially round rope cross-section. Such a flattening to an elliptical cross-sectional shape is dependent on the ratio of the diameter of the round cylinder to the diameter of the rope as well as the tensile load with which the rope during the winding process is claimed. Since the rope diameter is small compared to the diameter of the cylinder and the rope just has to be wound so tightly that it does not slide off the cylinder, the change in shape to the elliptical cross section and thus the cross-sectional area change is small. As can be demonstrated with the Bredt's formulas known from the technical mechanics, the torsional strength of the slightly flattened cross section is thus only slightly changed. In addition, other variants of the shaping body 100 conceivable, although this can also be used as a lost form.

By winding the spring element semi-finished product gets a spiral-like shape. To the final (Faserverbundwerkstoff-) spring element 200 It is then produced in a curing device or heating chamber 118 driven, in which the matrix material 78 , preferably a reaction resin, hardens and that spring element 200 gets a stable form. For curing can be used instead of the heat chamber 118 , In particular, depending on the type of resin used, a UV light chamber or the like are used.

The continuously wound and now cured fiber composite spring element 200 , now also referred to as a spiral spring, can at the joint of two shaping body 100 . 102 . 104 by means of a separating device 120 be separated, so that one or more shaping body 100 . 102 . 104 together with the (Faserverbundwerkstoff-) spring element thereon 200 can be removed from the production. After pulling out the foil strip 116 receives the spring element 200 a game to the surface of the shaping body and can be unwound from this or stripped. Subsequently, the shaping body the magazine 90 be returned. This enables a continuous manufacturing process.

Depending on the intended use of the spiral fiber composite spring element 200 a corresponding type of rope must be selected. For train-pressure springs come ropes 10 with opposing, interwoven winding or oppositely layered wound ropes 10 into consideration. In particular, care must be taken that a very close-meshed interweaving takes place, since otherwise due to the pressure component from the normal stresses of the reinforcing fiber sheath 30 to unwind the appropriately oriented thread bundles 36 . 37 and to a destruction of the spring element semifinished product 10 can lead. For spring element semi-finished products 10 with unilateral loading are ropes 10 with rectified winding of the thread bundle 36 . 37 suitable. Special attention is therefore on the winding direction of the thread bundles 36 . 37 during rope making and the subsequent winding of the rope 10 around the forming body 100 to judge.

The methods described above are preferably carried out fully automatically, but are in principle also manually executable. Furthermore, in particular small series with spring element semifinished products 10 large dimension with a lost positive shape, z. B. a cylindrical molding body with a semicircular groove made of hard foam plastic or molding sand. The lost form can be destroyed to remove the hardened spring. Due to the great hardness of the fiber materials are used for the tool 40 , in particular the base body 42 , Materials made of hardened and polished steel alloys or suitable ceramics used.

Furthermore, when using appropriate resin types for the matrix material 78 the rope 10 also be provided as a "prepreg" and contains the resin required for curing in a rubber-elastic, dry state. Correspondingly treated ropes 10 can be stored on rolls for further processing. Thus, no elaborate systems are required for impregnation and the prefabricated ropes 10 can with the shaping body 100 be brought into a spiral shape and then in a heat chamber 118 be cured.

With the winding method described above are preferably spiral or cylindrical (Faserverbundwerkstoff-) spring elements 200 or coil springs produced. Alternatively, but also flat spring elements 200 or spring elements 200 be formed with rectangular cross-section and slightly rounded corner radii.

The molded with the novel spring element semi-finished products 10 have a density greater than or equal to about 1.9 g / cm ³ . For spring element semifinished products 10 greater dimension, the density can be less than 1 g / cm ³ , since in this case as a material for the spring core body 20 lightweight plastic foams can be used and make up the bulk of the spring volume. The actual torsional load carrying reinforcing fiber sheath 30 takes up only a small part of the spring weight. The weight of a spring made of fiber composite material is therefore at least 60% lower than that of a comparable steel spring.

In the winding of the spring element semifinished product 10 around the spring form forming spring shaped body 100 the orientation of the bundles of fibers remains 36 . 37 received in the rope. Ideally, the pitch of the helical winding is the filament bundle 36 . 37 about 45 ° to the longitudinal direction L of the spring core body 20 inclined. The comparatively thin annular cross section of the reinforcing fiber sheath 30 takes the case of such fiber composite spring elements 200 decisive torsional stress ideal. In the direction of the fiber flow, only normal stresses occur, whereby the direction-oriented material properties can be ideally exploited. Here comes the larger compared to the material steel modulus of elasticity of the fiber material to fruition. The almost negligible transverse forces takes the spring core body 20 on. Due to the high dynamic alternating strength of composite materials compared to conventional steel, the fiber composite spring elements according to the invention 200 an increased life. In addition, fiber composite spring elements 200 Made of fiber-reinforced plastic resistant to a variety of corrosive media.

LIST OF REFERENCE NUMBERS

10

Spring element semis

20

Spring core body

30

Reinforcing-fiber sheath

32

thread

36

thread bundle

37

thread bundle

38

layer

40

Tool

42

base body

43

drilling

44

delivery channel

45

feeding

46

injection area

47

compression region

48

discharge area

50

connection

52

supply

54

annular channel

56

drilling

58

injection molding machine

70

role

72

idler pulley

74

jig

75

jig

76

drinking trough

78

Matrix material

80

catch basin

82

Return line

90

magazine

100

body shaping

102

body shaping

104

body shaping

107

first end

108

second end

110

connection

116

foil tape

118

heat chamber

120

separating device

200

Fiber composite spring element

L

longitudinal direction

F

conveying direction

D _e

first diameter

D _k

second diameter

D _a

third diameter

D _l

fourth diameter

Claims (27)

Method for producing a cable-like spring element semifinished product ( 10 ), comprising the following steps: a) providing an elastically and reversibly compressible spring core body ( 20 ) of a spring core body ( 20 ) surrounding, at least one fiber filament ( 32 ) having reinforcing fiber sheath ( 30 ); b) impregnating at least the reinforcing fiber sheath ( 30 ) with a liquid or pasty, curable matrix material ( 78 ), and thereby Determining a preliminary mutual arrangement of the spring core body ( 20 ) and the reinforcing fiber cladding ( 30 ) and forming a predetermined cross-sectional shape of the spring element semifinished product ( 10 ), wherein the spring element semifinished product ( 10 ) is compressed during the impregnation and / or after the impregnation and in this case elastically and reversibly deformed, and wherein during the compression of the spring core body ( 20 ) is compressed and so by means of the spring core body ( 20 ) against the inside of the reinforcing fiber sheath ( 30 ) directed back pressure is generated. Method according to claim 1, characterized in that the spring core body ( 20 ) on its outside against penetration of the liquid or pasty curable matrix material ( 78 ) is sealed. Method according to claim 1 or 2, characterized in that the spring core body ( 20 ) for the liquid or pasty curable matrix material ( 78 ) is impermeable. A method according to claim 1, characterized in that in step b) also the spring core body ( 20 ) is soaked. Method according to one of the preceding claims, characterized in that when impregnating an excess amount of the matrix material ( 78 ) is supplied. Method according to one of the preceding claims, characterized in that the with the reinforcing fiber sheath ( 30 ) surrounded spring core body ( 20 ) for impregnation with an excess amount of the matrix material ( 78 ) by a with the liquid or pasty, curable matrix material ( 78 ) filled drinking bowl ( 76 ). Method according to one of claims 1 to 5, characterized in that the with the reinforcing fiber sheath ( 30 ) surrounded spring core body ( 20 ) for impregnation through a conveyor channel ( 44 ) and the liquid or pasty curable matrix material ( 78 ) in the conveyor channel ( 44 ) is injected. Method according to one of the preceding claims, characterized in that the spring element semifinished product ( 10 ) after soaking through a conveyor channel ( 44 ) is transported. Method according to one of the preceding claims, characterized in that after impregnation any excess matrix material ( 78 ) Will get removed. A method according to claim 9, characterized in that the removal of the excess matrix material ( 78 ) via the delivery channel ( 44 ) or by means of the delivery channel ( 44 ) he follows. Method according to one of claims 9 or 10, characterized in that removed excess liquid or pasty curable matrix material ( 78 ) ( 78 ; 80 ) and used again for drinking ( 78 ; 82 ) becomes. Method according to one of the preceding claims, characterized in that in a step c) the matrix material ( 78 ) is at least partially cured, so that the spring element semifinished product ( 10 ) has a prepreg-like and largely dry, limp, rope-like state. Tool for processing a cable-like spring element semifinished product ( 10 ) with a delivery channel ( 44 ), through which the spring element semifinished product ( 10 ) is conveyable and in the conveying direction (F) a feed area ( 45 ), a compression area ( 47 ) and a discharge area ( 48 ), wherein the conveyor channel ( 44 ) in the conveying direction (F) from an input of the feed region ( 45 ) to the compression area ( 47 ), and wherein the cross-sectional area or the diameter (D _e ) of the input of the feed area ( 45 ) greater than or equal to the outer diameter of the in the delivery channel ( 44 ) subsidized spring element semifinished product ( 10 ), and wherein the cross-sectional area or the diameter (D _K ) of the compression region ( 47 ) smaller than the desired cross-sectional area to be formed or the desired outer diameter of the spring element semifinished product ( 10 ). Tool according to claim 13, characterized in that between feed area ( 45 ) and compression range ( 47 ) an injection area ( 46 ), and in the area of the injection area ( 46 ) at least one bore ( 56 ) in the conveyor channel ( 44 ), through which the spring element semifinished product ( 10 ) the liquid or pasty, hardenable matrix material ( 78 ) can be fed. Tool according to claim 13 or 14, characterized in that the cross-sectional area or the diameter (D _A ) of the discharge area ( 48 ) substantially equal to or larger than the desired cross-sectional area to be formed or the desired outer diameter of the spring element semifinished product ( 10 ). Method for producing a helical spring element ( 200 ), wherein with a method according to one of claims 1 to 12 a rope-like spring element semifinished product ( 10 ) is prepared and then by winding the soaked Spring element semifinished product ( 10 ) around a shaping body ( 100 ) with a surface which is based on the final geometric shape of the spring element ( 200 ) and / or depicts it; and by complete curing ( 118 ) of the liquid or pasty, curable matrix material ( 78 ) the rope-like spring element semifinished product ( 10 ) to a spiral-shaped spring element semifinished product ( 10 ) and by curing from the spiral spring element semifinished product ( 10 ) the helical spring element ( 200 ) will be produced. A method according to claim 16, characterized in that on the shaping body ( 100 ) another shaping body ( 102 . 104 ) by means of a torsion-proof, preferably form-fitting, connection ( 110 ) is connected. A method according to claim 16 or 17, characterized in that the further shaping body ( 102 . 104 ) is connected with or without interrupting the winding process. Method according to one of claims 16 to 18, characterized in that the liquid or pasty, hardenable matrix material ( 78 ) by means of heat ( 118 ) and / or cured by a photochemical reaction, in particular by means of UV radiation. Method according to one of claims 16 to 19, characterized in that before step a) a band, preferably a foil strip ( 116 ), predetermined thickness on the shaping body ( 100 . 102 . 104 ) is wound. Method according to one of claims 16 to 20, characterized in that the hardened spiral spring element ( 200 ) is cut to a predetermined length ( 120 ) becomes. Method according to one of claims 16 to 21, characterized in that the spring core body ( 20 ) after complete curing of the liquid or pasty curable matrix material ( 78 ) from the spiral spring element ( 200 ) Will get removed. Device for producing a helical spring element ( 200 ) with a hollow, tubular fiber composite spring element body ( 30 ), comprising a drinking basin ( 76 ) for impregnating a cable-like spring element semifinished product ( 10 ), a tool ( 40 ) according to one of claims 13 to 15, at least one shaping body ( 100 ) for forming the cable-like spring element semifinished product ( 10 ) in a spiral spring element semifinished product ( 10 ), wherein the shaping body ( 100 ) one on the geometric shape of the spiral spring element semifinished product ( 200 ) or surface reflecting this shape ( 106 ) and at least one end ( 108 . 109 ) a connection to the connection ( 110 ) with a further shaping body ( 102 . 104 ), a curing device ( 118 ) for curing the helical spring element semifinished to form the spiral spring element ( 200 ). Device according to claim 23, characterized by at least one tensioning device ( 74 . 75 ) for tensioning the cable-like spring element semifinished product ( 10 ). Apparatus according to claim 23 or 24, characterized by a catch basin ( 80 ) for collecting excess matrix material. Device according to one of claims 23 to 25, characterized by a return line ( 82 ) containing the excess matrix material ( 78 ) from the catch basin ( 80 ) to the drinking basin ( 76 ). Device according to one of claims 23 to 26, characterized by a separating device ( 120 ) for cutting the rope-like, the spiral-shaped spring element semifinished product ( 10 ) or the spiral spring element ( 200 ).

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